Grinding wheel



MarCh31, 1942. 1 BAUER 2,278,301

GRINDING WHEEL Filed Feb. '12, 1941 Patented .Mar. 31, 1942 UNITE-D STATE GRINDING WHEEL Hans E. Bauer, Philadelphia, Pa., assignor to Abrasive Company, Philadelphia, Pa., a corporation of Pennsylvania Application February 12, 1941, Serial No. 378,670

' 2 Claims.

This invention relates to new and useful improvements in grinding wheels of the molded type and more particularly to a novel mounting insert and reinforcing means therefor.

Grinding wheels of the type mentioned are generally bonded of synthetic resins, rubber, shellac, and like materials and are employed for a numberof uses. Usually molded grinding wheels bonded of these materials are provided with heavy cumbersome mounting inserts which are expensive to manufacture and do not provide adequate support and weinforcement for the molded abrasive material. Too, such mountings as have been used heretofore are quite heavy and, therefore, grinding wheels equipped with such mountings are proportionately heavier and hard to handle.

With the foregoing in mind, the invention has for its primary object the provision of a molded grinding wheel wherein there is provided a novel mounting insert which is relatively light in weight, comparatively less expensive to manufacture and which also imparts to the wheel considerably greater strength and holding power against disintegration than has been possible to obtain heretofore in wheels of this type.

Another object of the invention is to provide a-molded grinding wheel having a mounting insert as set forth which is permanently associated with said wheel and constructed and arranged so,

as to insure a substantially perfect balanced wheel while permitting unitary or composite fabrication thereof.

These and other objects of the invention as well as the various features and details of the construction and arrangement thereof are hereinafter fully set forth and described and shown in the accompanying drawing, in which:

Figure 1 is a view in perspective of one part of a mounting insert embodying the present in"- vention for molded grinding wheels.

Figure 2 is a view similar to Figure 1 showing another part of the mounting insert.

Figure 3 is a view in section diametrically through a grinding wheel having a mounting insert made according to the present invention; and

B is'shaped into the cup-like form by means of a mold in the conventional manner, and the mounting insert M is embedded and bonded into the said body B during molding thereof.

The mounting insert M comprises two insert elements 2 and 3 permanently secured together and each consisting essentially of an annular disk portion 2a or 3a and a centrally located projecting tubular hub or sleeve portion 2b or 3b respectively as the case may be. These insert elements 2 and 3 preferably are stamped from sheet metal of high strength and durability and they are, therefore, relatively light in weight.

In the embodiment of the invention illustrated in the drawing, the disk portion 2a of the insert element 2 is of comparatively. greater diameter than the disk portion 3a of the element 3 and its periphery is provided with a plurality of lugs t extending in the general direction parallel to the sleeve portion 2b. The central hub or sleeve portion 2b of the insert element 2 has an internal diameter sufficiently large to receive telescopically therein the central hub or sleeve portion 3b of the other insert element 3 in the general direction shown in Figure 3 of the drawing. It will be observed that the sleeve portion 3b of element 3 extends entirely through the sleeve portion 2b of the other element 2 and the free end edge of said sleeve 3b is coined or turned outwardly over the inner edge of the annular disk portion 2a as indicated at 5. The internal bore of the hub or sleeve portion 3b of the element 3 may .be provided with threads 6 on at least a portion of its length so that the wheel may be screwed onto a threaded arbor 7 to be 'rotatively driven thereby, and said threads 6 are formed in a direction opposite to the direction of rotary movement of the wheel so that the latter remains on the arbor l during rotation. However, threads 6 may be dispensed-with and the wheel mounted on its arbor or shaft by suitable clamping disk members or the like in well known manner.

Before fabricating the wheel I, the insert elements 2 and 3 are first assembled in the telescoping relationpreviously described and then secured together by spot welding together the inner surface of the .disk portion 3a ofethe element 3 and the annular end face of the. ,hub

a mounting insert M. The grinding wheel body portion 2b of the other element 2, for example, at the several points intended therefor by the recesses 8 provided in the outer surface of said disk portion 3a. However, the elements 2 and 3 may, if desired, be welded together at any other suitable location such as, for example, about the Junction of the hub portion 2b and the disk portion 3a as indicated at 9. After the elements 2 and 3 have been welded together as aforesaid, the free end edge of the sleeve portion may be coined or turned outwardly as'at 5 over the inner edge of disk portion 2a and the internal bore of the sleeve portion 3b may be provided with threads 6 as previously described.

With the elements 2 and 3 thus permanently joined together and provided with threads 6, the now complete mounting insert M is embodied in the wheel by shaping and molding the abrasive material of the body B about said insert so that the latter is correctly positioned and embedded centrally in the base portion la of the wheel with the outer surfacesof the disk portions 2a and 3a of said insert M residing respectively flush with the outer and inner surfaces of said central or base portionof the abrasive material while the projections or lugs i at the periphery of the said disk portion 2a extend inwardly of the abrasive body B of the wheel in the direction of but spaced a substantial distance radially outward from the axis of rotation of said wheel.

From the foregoing description it will be seen that the elements 2 and 1 3 form an integral mounting insert structure M that becomes in turn an integral part of the grinding wheel I and, while the outer surfaces of the disk portions 2a and 3a of said elements are exposed to view in the surfacesof the wheel central base portion, the molded abrasive material is securely bonded to the inner surfaces of said disk portions to and 3a and to the outer surface of the hub or sleeve portion 217, and is additionally keyed to the mounting insert M by means of the axially extending projections or lugs 4 which hold the wheel together against the action of centrifugal force exerted thereon duringoperation and use thereof.

- A'modification of the invention is shown in Figure 4 of the drawing and in this particular embodiment the mounting insert M is in the the drawing, 'nor are the diameters of the disk portions 2a and 3a limited to the particular size relationship shown since said disk portions may be of the same diameter, or otherwise, as desired or required by the particular type 'of grinding wheel and the use to be made thereof. 'Ifoo, it is entirely within the comprehension of the invention that the telescopic relation of the sleeve portions 2b and 31) may be reversed so that the former is received within the latter.

While certain embodiments of the invention have been set forth and described herein, it is not intended to 'limit the invention to such disclosure but that changes and variations may be made and incorporated therein within the scope of the annexed claims.

I claim:

1. A moldedcup-shaped article of the character described comprising a circular body member having a continuous side wall and a base portion provided with an axial bore centrally therein, and a composite, mounting embedded and bonded in the base portion of the body at and adjacent the bore therein, said mounting comprising a central sleeve portion lining the bore in the base portion of said body member and spaced annular disk portions disposed respectively with their outer surface flush in the inner and outer surfaces of the body member base portion; the disk portion disposed in the outer surface of th'e base portion having a diameter greater than the diameter of the inner surface of said base portion, and lugs arranged peripherally of the disk portion in the outer surface of the base and projecting into the body member in a zone outwardly of the junction of the inner surfaces of the side wall and base portions of said body member and in alignment with said side wall.

form of a one-piece pressure die-casting l0. It

will be observed, however, that the shape, arrangement and dimensions of this casting l0 conform substantially to the insert previously described and composed of the two stamped sheet metal insert elements 2 and 3 respectively, and embody relatively spaced annular disk portions I00. and lllb, respectively, connected together by a hub or sleeve portion lilo which may be internally threaded as indicated at Ba, the disk portion lilb being provided at its periphery with lugs to which project in radially spaced relation with respect to the axis of the sleeve or hub portion We of the insert.

The present invention provides a grinding wheel of the molded or bonded type having a novel mounting insert which is relatively light in weight, comparatively inexpensive to manufacture and which imparts to the wheel a high degree of strength and holding power against disintegration from the action of centrifugal force thereon. Too, the invention provides a mounta ing insert that is permanently associated with the wheel and its construction and arrangement is such as to permit of unitary or composite fabrication of said wheel.

The invention, of course, is not limited in use illustrated in to abrasive wheels of the cup-type full 2. A molded cup-shaped article of the character described comprising a circular body member having a continuous side wall and a base portion provided with an axial .bore centrally therein, and a composite mounting embedded and bonded in the base portion of the body at and adjacent the bore therein, said mounting comprising two insert elements each having an annular disk portion and a central sleeve portion, the sleeve portion of one of said elements being telescoped within the sleeve portion of the other element and lining the bore in the base portion of said body member and the sleeve portion of said other element having its end in contact with and permanently welded to the inner surface of the disk portion of said one element, the annular disk portions being axially spaced and disposed respectively with their outer surface flush in the inner and outer surfaces of the body member base portion, the disk portion disposed in the outer surface of the base portion having a diameter greater than the diameter of the inner surface of said base portion, and lugs arranged peripherally of the disk portion in the outer surface of the base and projecting into the body member in a zone outwardly of the junction of the inner surfaces of the side wall and base portions of said body member and in alignment with said side wall.

HANS E. BAUER. 

